2022-04-28 13:48:31

by Jan Kara

[permalink] [raw]
Subject: Re: [PATCH -next v4 3/3] block, bfq: do not idle if only one group is activated

On Thu 28-04-22 19:19:07, Yu Kuai wrote:
> Now that root group is counted into 'num_groups_with_busy_queues',
> 'num_groups_with_busy_queues > 0' is always true in
> bfq_asymmetric_scenario(). Thus change the condition to '> 1'.
>
> On the other hand, this change can enable concurrent sync io if only
> one group is activated.
>
> Signed-off-by: Yu Kuai <[email protected]>

Looks good. Feel free to add:

Reviewed-by: Jan Kara <[email protected]>

Honza

> ---
> block/bfq-iosched.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
> index 609b4e894684..aeba9001da0b 100644
> --- a/block/bfq-iosched.c
> +++ b/block/bfq-iosched.c
> @@ -844,7 +844,7 @@ static bool bfq_asymmetric_scenario(struct bfq_data *bfqd,
>
> return varied_queue_weights || multiple_classes_busy
> #ifdef CONFIG_BFQ_GROUP_IOSCHED
> - || bfqd->num_groups_with_busy_queues > 0
> + || bfqd->num_groups_with_busy_queues > 1
> #endif
> ;
> }
> --
> 2.31.1
>
--
Jan Kara <[email protected]>
SUSE Labs, CR